2x + y = 20
-5y = -6x + 12
To use the substitution method, first isolate one of the variables in one of the equations.
Isolate the "y" in the first equation (because it is the easiest to isolate), and substitute it into the second equation:
2x + y = 20 Subtract 2x on both sides
y = 20 - 2x
-5y = -6x + 12 (since y = 20 - 2x, you can substitute 20 - 2x into y)
-5(20 - 2x) = -6x + 12 Multiply -5 into (20 - 2x)
-100 + 10x = -6x +12 Add 100 on both sides
10x = -6x + 112 Add 6x on both sides
16x = 112 Divide 16 on both sides
x = 7
Now that you have found x, you can substitute 7 into x for one of the original equations:
2x + y = 20
2(7) + y = 20
14 + y = 20 Subtract 14 on both sides
y = 6
-5y = -6x + 12
-5y = -6(7) + 12
-5y = -42 + 12
-5y = -30 Divide -5 on both sides
y = 6
x = 7, y = 6
10 * 100 = 1000 so... 10^3 would equal 1000 too
Answer:
Step-by-step explanation:
Original equation
√x+6-4 = x
Isolate
√x+6 = 4+x
Raise both sides to the second power
(√x+6)2 = (4+x)2
After squaring
x+6 = x2+8x+16
Rearranged equation
x2 + 7x + 10 = 0
This equation has two rational roots:
{x1, x2}={-2, -5}
Original equation, root isolated
√x+6 = 4+x
Plug in -2 for x
√(-2)+6 = 4+(-2)
Simplify
√4 = 2
Solution checks !!
Solution is:
x = -2
Original equation, root isolated
√x+6 = 4+x
Plug in -5 for x
√(-5)+6 = 4+(-5)
Simplify
√1 = -1
Solution does not check
1 ≠ -1
Answer:
x= 226/3 or 75.33333333333333333333333333333
Step-by-step explanation:
14y+82=6x-20
y=25
Sub y=25 into 14y+82=6x-20
14y+82=6x-20
14(25)+82=6x-20
Calculate as follows:
14(25)+82=6x-20
350+82=6x-20
432=6x-20
Add twenty to both sides:
432+20=6x-20+20
452=6x-0
452=6x
Divide both sides by 6
452=6x
452/6=6x/6
452/6=x
x= 226/3 or 75.33333333333333333333333333333
Answer:
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Step-by-step explanation:
